No, there was a lot of misinformation stating that only wire diameter will change the spring rate of a compression spring. The anti-roll bar analogy you used was supposed to be simplify explanation, but the anology was not actually correct in how spring rate was affected.

In regards to active coils and spring rate change, as the number of active coils on a compression spring goes up, the spring rate will go down because the total wire length used in the spring has increased. When comparing wire diameter to number of coils, the wire diameter of a spring is a much more sensative parameter to change. For example, after a quick calc, a 10% change in number of coils results in a ~11% change in spring rate, while a 10% change in wire diameter will result in a ~33% change in spring rate!

Wire material is typically ASTM A228, but the relationship is directly proportional to spring rate. If you used a material with twice the modulous of rigidity, you get double the spring rate.

I think the biggest concern when visual inspecting and matching springs you have (since most don't have a way of measureing) is to count the number of coils and measure the ID of the spring (since the ID tolerance has a significant influence on spring rate). If these two parameters are close then it is likely that the two springs will be close in spring rate. The free length is not as critical of a perameter since it does not influence spring rate, BUT since it is longer...for the same spring rate compared to a shorter free length spring it will produce a higher total force when fully compresed (but will progress at the same rate). Since our shocks have preload adjustment this can be accounted for (i.e. a slightly longer spring would be set higher up on the shock body than a short spring, so that it achieces the same preload).

I hope that answers your question, if not feel free to re-word and I'll try again.